X-ray photoelectron spectroscopy studies on single crystalline β-FeSi2

In order to realize the photoluminescence of semiconducting β-FeSi2 homoepitaxial films, surface preparation of single crystalline β-FeSi2 is of critical importance. An atomically flat and clean substrate surface of β-FeSi2 was prepared by sputtering with 2 keV Ar+ ions or by heating at 850 °C. The structure of the native surface oxide and the removal of this layer were investigated though X-ray photoelectron spectroscopy measurements. No significant deviation of the stoichiometry was detected in the surface region. Our results suggest that a surface prepared in this way is an eligible substrate for homoepitaxy of β-FeSi2.